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Loans - Loan Balances (Detail) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025	Dec. 31, 2024
Accounts Notes And Loans Receivable [Line Items]
Total loans	$ 3,229,667	$ 3,270,046
Allowance for credit losses	(40,536)	(42,020)	$ (40,284)	$ (39,669)
Net loans	3,189,131	3,228,026
Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	3,229,667	3,270,046
Allowance for credit losses	(40,536)	(42,020)
Net loans	3,189,131	3,228,026
Commercial and Agriculture [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	310,400	308,692
Allowance for credit losses	(4,996)	(5,153)	(6,194)	(6,586)
Commercial and Agriculture [Member] \| Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	310,400	308,692
Commercial Real Estate Owner Occupied [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	390,786	385,547
Allowance for credit losses	(4,280)	(4,420)	(4,466)	(4,327)
Commercial Real Estate Owner Occupied [Member] \| Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	390,786	385,547
Commercial Real Estate Non Owner Occupied [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	1,232,781	1,239,017
Allowance for credit losses	(11,789)	(12,118)	(11,412)	(11,404)
Commercial Real Estate Non Owner Occupied [Member] \| Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	1,232,781	1,239,017
Residential Real Estate [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	943,425	944,328
Allowance for credit losses	(14,486)	(14,718)	(12,455)	(11,866)
Residential Real Estate [Member] \| Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	943,425	944,328
Real Estate Construction [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	254,254	285,137
Allowance for credit losses	(3,502)	(3,842)	(4,017)	(3,708)
Real Estate Construction [Member] \| Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	254,254	285,137
Farm Real Estate [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	32,700	37,775
Allowance for credit losses	(225)	(279)	(264)	(226)
Farm Real Estate [Member] \| Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	32,700	37,775
Lease Financing Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	32,693	35,103
Allowance for credit losses	(1,008)	(1,169)	(1,277)	(1,361)
Lease Financing Receivable [Member] \| Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	32,693	35,103
Consumer and Other [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	32,628	34,447
Allowance for credit losses	(250)	(321)	$ (199)	$ (191)
Consumer and Other [Member] \| Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	$ 32,628	$ 34,447